🔖 release version [email protected] (#138)

### TL;DR
This pull request updates the version of the `pyrb` package from `0.10.8` to `0.10.9`.

### What changed?
- The version number in `pyproject.toml` has been incremented from `0.10.8` to `0.10.9`.

### How to test?
No testing is specifically required, as this change only updates the version number.

### Why make this change?
The version bump likely includes important updates, bug fixes, or new features that justify releasing a new version of the package.

---

backend/pyproject.toml

@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "pyrb"
-version = "0.10.8"
+version = "0.10.9"
 description = "Python Rebalancer"
 authors = ["Minki Kim <[email protected]>"]
 readme = "README.md"